LOL, Dsnuts, I didn't even have a chance to give my first impressions before you jumped in.
So while I enjoy the CKM500's sound, they have been relegated to home listening because they are just not ergonomic for my everyday subway commute. That extension cord part bugs the heck out of me because of its weight, and it tends to get in the way.
I have been auditioning the FX40 to take over as my everyday beater. Honestly, for my ears however, they are just a tad too piercing. I tested them several times at the store over multiple and separate days. Unfortunately I couldn't get comfortable with the FX40, so didn't buy them. For the right preferences, they are definitely very capable; fast, crisp, good bass.
I tried the FX1X next, and these were just eh. Sounded a bit muddy to me. Tried the FX3X next, and immediately felt comfortable with the sound, in-ear fit, ruggedness, and soft cord.
For me, the FX3X are the alternative to CKS77, with less boomy overwhelming (ear-filling) bass and still great mids/highs. Bass is still featured on the FX3X but slightly more laid-back (compared to CKS77). Soundstage is smaller than CKS77 and CKM500; it's not as airy or spacious. Highs are clear and mids are smooth, balanced together with the low-end. The overall listening experience is good laid-back and really really smooth for my ears. Bass quantity is nearly exactly what I was looking for.
In terms of technical competence and musicality, I think CKM500 are still tops among all of these. But the FX3X are a great find and will be awesome for my everyday use.
As a side note, it looks like the FX3X were released at the same time together with the FX1X in Japan, so technically "older" than the FX101. Let me know what you think when you receive them.